core/ difference with XFA (for information only).

core/src/fpdftext/fpdf_text_int.cpp

Index: core/src/fpdftext/fpdf_text_int.cpp
diff --git a/core/src/fpdftext/fpdf_text_int.cpp b/core/src/fpdftext/fpdf_text_int.cpp
index 4ed11e3986cb757183939f4947f873a6176833cf..c69ffc8ee831cd0c5de256082a8562ece5b577c4 100644
--- a/core/src/fpdftext/fpdf_text_int.cpp
+++ b/core/src/fpdftext/fpdf_text_int.cpp
@@ -1525,8 +1525,52 @@ void CPDF_TextPage::ProcessTextObject(PDFTEXT_Obj Obj) {
   int nItems = pTextObj->CountItems();
   FX_FLOAT baseSpace = _CalculateBaseSpace(pTextObj, matrix);
 
+#ifndef PDF_ENABLE_XFA
   const FX_BOOL bR2L = IsRightToLeft(pTextObj, pFont, nItems);
   const FX_BOOL bIsBidiAndMirrorInverse =
+#else
+  FX_BOOL bIsBidiAndMirrosInverse = FALSE;
+  CFX_BidiChar* BidiChar = new CFX_BidiChar;
+  int32_t nR2L = 0;
+  int32_t nL2R = 0;
+  int32_t start = 0, count = 0;
+  CPDF_TextObjectItem item;
+  for (int32_t i = 0; i < nItems; i++) {
+    pTextObj->GetItemInfo(i, &item);
+    if (item.m_CharCode == (FX_DWORD)-1) {
+      continue;
+    }
+    CFX_WideString wstrItem = pFont->UnicodeFromCharCode(item.m_CharCode);
+    FX_WCHAR wChar = wstrItem.GetAt(0);
+    if ((wstrItem.IsEmpty() || wChar == 0) && item.m_CharCode) {
+      wChar = (FX_WCHAR)item.m_CharCode;
+    }
+    if (!wChar) {
+      continue;
+    }
+    if (BidiChar && BidiChar->AppendChar(wChar)) {
+      CFX_BidiChar::Direction ret = BidiChar->GetBidiInfo(&start, &count);
+      if (ret == CFX_BidiChar::RIGHT) {
+        nR2L++;
+      } else if (ret == CFX_BidiChar::LEFT) {
+        nL2R++;
+      }
+    }
+  }
+  if (BidiChar && BidiChar->EndChar()) {
+    CFX_BidiChar::Direction ret = BidiChar->GetBidiInfo(&start, &count);
+    if (ret == CFX_BidiChar::RIGHT) {
+      nR2L++;
+    } else if (ret == CFX_BidiChar::LEFT) {
+      nL2R++;
+    }
+  }
+  FX_BOOL bR2L = FALSE;
+  if (nR2L > 0 && nR2L >= nL2R) {
+    bR2L = TRUE;
+  }
+  bIsBidiAndMirrosInverse =
+#endif
       bR2L && (matrix.a * matrix.d - matrix.b * matrix.c) < 0;
   int32_t iBufStartAppend = m_TempTextBuf.GetLength();
   int32_t iCharListStartAppend = m_TempCharList.GetSize();
@@ -1685,6 +1729,7 @@ void CPDF_TextPage::ProcessTextObject(PDFTEXT_Obj Obj) {
       }
     }
   }
+#ifndef PDF_ENABLE_XFA
   if (bIsBidiAndMirrorInverse) {
     SwapTempTextBuf(iCharListStartAppend, iBufStartAppend);
   }
@@ -1722,7 +1767,17 @@ FX_BOOL CPDF_TextPage::IsRightToLeft(const CPDF_TextObject* pTextObj,
     FX_WCHAR wChar = wstrItem.GetAt(0);
     if ((wstrItem.IsEmpty() || wChar == 0) && item.m_CharCode) {
       wChar = (FX_WCHAR)item.m_CharCode;
-    }
+#else
+  if (bIsBidiAndMirrosInverse) {
+    int32_t i, j;
+    i = iCharListStartAppend;
+    j = m_TempCharList.GetSize() - 1;
+    for (; i < j; i++, j--) {
+      std::swap(m_TempCharList[i], m_TempCharList[j]);
+      std::swap(m_TempCharList[i].m_Index, m_TempCharList[j].m_Index);
+#endif
+    }
+#ifndef PDF_ENABLE_XFA
     if (!wChar) {
       continue;
     }
@@ -1741,9 +1796,18 @@ FX_BOOL CPDF_TextPage::IsRightToLeft(const CPDF_TextObject* pTextObj,
       nR2L++;
     } else if (ret == CFX_BidiChar::LEFT) {
       nL2R++;
+#else
+    FX_WCHAR* pTempBuffer = m_TempTextBuf.GetBuffer();
+    i = iBufStartAppend;
+    j = m_TempTextBuf.GetLength() - 1;
+    for (; i < j; i++, j--) {
+      std::swap(pTempBuffer[i], pTempBuffer[j]);
+#endif
     }
   }
+#ifndef PDF_ENABLE_XFA
   return (nR2L > 0 && nR2L >= nL2R);
+#endif
 }
 int32_t CPDF_TextPage::GetTextObjectWritingMode(
     const CPDF_TextObject* pTextObj) {